The state of the art in general is shown in the FIG. 2. An insulating housing, that contains a switching element is located in an environment of high pressurized fluid. For example this can be a vacuum interrupter in a subsea application. The vacuum interrupter must not get in touch with the high pressures, which can reach 300 bar. Therefore a pole part is needed, that withstands the pressure and keeps an atmospheric environment of 1 bar inside. The high pressurized fluid around is insulating oil. This is in an enclosure on the seabed in order to prevent damage from contact with the seawater.
For the electrical connection to the switching element, a conducting lid is used. Furthermore there is arranged a conducting ring. These contacts have to provide a good electrical connection. As well, they are part of the housing and have to be tight against leakage and stable against the pressure on the outside environment at high pressure level.
In line with the vacuum interrupter, there is a drive, that operates on low voltage level. To have this appropriate for a medium voltage application, the housing parts have to be made of insulating material. Furthermore the volume can be filled with an insulating gaseous medium like SF6.
Such well known construction leads to the following disadvantages. The design according to FIG. 2 results in certain design criteria to fulfil electrical and mechanical requirements. The switching element and the drive are accommodated in the same housing.
But this results in relatively long distances to insulate the different potentials from each other. As a low voltage device connected to a control, the drive must not be affected by the high voltage in its vicinity.